I'm having a builder build a 2300 sq.ft. ranch house, with all Low-E double-hung windows. My house has a full (unfinished) basement, and the main 1st floor has 8ft. flat ceilings. The attic has R38 blown-in insullation and R15 fiberglass high-desisty batts in the wall. The sheathing on the house is all plywood with a R2.5 insulated sheathing on top of that, and wrapped with tyvek housewrap. Exterior is all brick veneer.
The HVAC sub-contractor hasn't used Manual-J or Manual-D for the sizingm duct design nor heat load calc'. The furnace is a Bryant VS 2 stage "The Plus 80v"(315AAV) sized for Input: High 110,000 and 72,500 Low and Output: High 89,000 & Low 59,000.
They are going to use a SEER 10 Bryant 3.5 ton (561CJ042-F) A/C unit. I've been trying to get the builder to reduce the size of the A/C unit (house is in Chicago suburb area) given concerns on not having proper humidity in house while running the A/C, excessive Electrical usage (Com Ed rates), and probably fast cycle on/off times.
The HVAC sub won't budge - I even offered to sign a release for sizing to release him from a wrong sized unit (thus going against his recommendation). The builder requested the HVAC do this, but the HVAC sub won't compromise. I can't understand that if thei model home with 10 ft great room, west facing clear windows, a vaulted study and Master Bedroom can possibleby be sized the same for A/C (the furnace was an upgrade I requested.
I've even sized things with the HVAC-Calc software that I bought, but the sub is "set in his ways" to be polite - What else could it be? Any ideas on this sizing, and anything to get a properly sized unit installed by the builder.
Thanks in advance!